Welcome to Rails¶ ↑
Rails is a web-application framework that includes everything needed to create database-backed web applications according to the Model-View-Controller (MVC) pattern.
Understanding the MVC pattern is key to understanding Rails. MVC divides your application into three layers, each with a specific responsibility.
The Model layer represents your domain model (such as Account,
Product, Person, Post, etc.) and encapsulates the
business logic that is specific to your application. In Rails,
database-backed model classes are derived from
ActiveRecord::Base
. Active Record allows you to present the
data from database rows as objects and embellish these data objects with
business logic methods. You can read more about Active Record in its README. Although most Rails models are
backed by a database, models can also be ordinary Ruby classes, or Ruby
classes that implement a set of interfaces as provided by the Active Model
module. You can read more about Active Model in its README.
The Controller layer is responsible for handling incoming HTTP
requests and providing a suitable response. Usually this means returning
HTML, but Rails controllers can also generate XML, JSON, PDFs,
mobile-specific views, and more. Controllers load and manipulate models,
and render view templates in order to generate the appropriate HTTP
response. In Rails, incoming requests are routed by Action Dispatch to an
appropriate controller, and controller classes are derived from
ActionController::Base
. Action Dispatch and Action Controller
are bundled together in Action Pack. You can read more about Action Pack in
its README.
The View layer is composed of “templates” that are responsible for providing appropriate representations of your application's resources. Templates can come in a variety of formats, but most view templates are HTML with embedded Ruby code (ERB files). Views are typically rendered to generate a controller response, or to generate the body of an email. In Rails, View generation is handled by Action View. You can read more about Action View in its README.
Active Record, Action Pack, and Action View can each be used independently outside Rails. In addition to them, Rails also comes with Action Mailer (README), a library to generate and send emails; Active Job (README), a framework for declaring jobs and making them run on a variety of queueing backends; and Active Support (README), a collection of utility classes and standard library extensions that are useful for Rails, and may also be used independently outside Rails.
Getting Started¶ ↑
-
Install Rails at the command prompt if you haven't yet:
gem install rails
-
At the command prompt, create a new Rails application:
rails new myapp
where “myapp” is the application name.
-
Change directory to
myapp
and start the web server:cd myapp rails server
Run with --help
or -h
for options.
-
Using a browser, go to
http://localhost:3000
and you'll see: "Welcome aboard: You're riding Ruby on Rails!" -
Follow the guidelines to start developing your application. You may find the following resources handy:
Contributing¶ ↑
We encourage you to contribute to Ruby on Rails! Please check out the Contributing to Ruby on Rails guide for guidelines about how to proceed. Join us!
Code Status¶ ↑
License¶ ↑
Ruby on Rails is released under the MIT License.